Phenotypic development is strongly influenced by inherited and environmental factors in adaptive and in non-adaptive ways. The outcome and duration of the effects of environmental circumstances, such as exposure to stressful conditions, vary with the severity of the stressor and with the life stage at which they are experienced. Physiological processes, such as stress responsiveness and growth rate can be affected, as can life history traits such as reproductive scheduling and longevity. Inherited factors can also have diverse effects that can span more than one generation. Early life is a particularly sensitive period since the phenotypic architecture is forming at this stage. Parental care can buffer the developing organism from environmental variation, but also give parents the potential to shape offspring phenotype to gain the best fitness outcome. The capacity of parents to buffer offspring from adverse conditions during development can vary with parental age, which can also affect inherited components. I will discuss these effects and present data from experimental work that we have conducted using zebra finches, and from some related work in the wild.